[okayama]

1st scramble: L2 F2 R F2 L B2 D2 L2 B2 D2 R F' L' B' D L B R' D2 U' F2
1st solution (1-hour): B U F L B F' L2 F' B' U' F' U' F B2 L' D' L U L' D L B2 U' B' U B' U2 B' U B2 U2 (31 moves)

Spoiler (Click to View)

Orient edges: B U F L
2x2x2 block: B F' L2 F'
2x2x3 block: B' U' F' U' F
All but 3 corners: B2 * U B2 U' B' U B' U2 B' U B2 U2 (found on inverse)

Insert at *: L' D' L U L' D L U'

After 2x2x2 block, there were some continuations, such as

2x2x3 block: B' U' B2 F' U' F
c/e pairs: B'

or

[1] Siamese 2x2x2 block: D' U2 F' U2 F D
[2] Siamese 2x2x2 block: D' U' F' U F D
[3] Siamese 2x2x2 block: D' R U R' D

but I couldn't find any good finish.

1st scramble: L2 F2 R F2 L B2 D2 L2 B2 D2 R F' L' B' D L B R' D2 U' F2
1st solution (after 1-hour): B U F B L F L' B' L R2 F2 D F' D' R2 F B L2 D F' U' F D' F' U (25 moves)

Spoiler (Click to View)

(Inverse)
Pre-scramble: L' F' U' B' (EO from my 1-hour solve)

2x2x2 block: F L2 B'
2x2x3 block: F' R2 D F D'
All but 4 corners: F2 R2 F'
Corner 3-cycle: F L' B L F' L' B' L
Correction: L' F' U' B'

Insert at the beginning: U' F D F' U F D' F'

2nd scramble: U' B2 D' L2 F2 U F2 U F2 D2 F2 L U F2 U2 B U B2 U2 R' U
2nd solution (1-hour): F R' U' D F D' F D' F' D2 F D' F' D2 F D F' D F U B' D L' D' B' L2 B' F U' (29 moves)

Spoiler (Click to View)

Firstly, I found the following solution (30 moves)
c/e pairs: F R'
Two squares: U' D F2 U
F2L minus 1 slot: D2 B2 * L F U2 B' +
Orient edges: U2 F U2 F'
All but 3 twisted corners: L' U L U

Insert at *: B L F2 L' B' L F2 L'
Insert at +: R D2 R' U2 R D2 R' U2

In the remaining time, I found the following solution.

(Inverse)
Pre-scramble: U' F2 D' U R F'

2x2x2 block: U F'
More square: B L2 B
Finish F2L: D L D' B
Correction of the first premove: U'
LL: F' D' F D' F' D2 F, D, F' D2 F D F' D F
Correction of the rest premoves: F2 D' U R F'

3rd scramble: B U2 F2 L2 U2 F D2 B2 R2 D2 F' R U' F U2 B' L' B' F2 D U
3rd solution (1-hour): B2 R' B' D U2 R' U2 F' D B2 U R2 U' R U' R' B' R' D B U B' D' B U' R' B' R B R (30 moves)

Spoiler (Click to View)

1st square: B2 R' B'
2nd square: D U2 R' U2
2x2x3 block: F' D B2
F2L minus 1 slot: U R2 U' R U'
All but 3 corners: R' B' R' * B R' B' R B R

Insert at *: D B U B' D' B U' B'

There are some short block-building starts, such as
B2 R' B' F' D2 U2 with premoves U2 B2, but I couldn't
find any better solution in time.

3rd scramble: B U2 F2 L2 U2 F D2 B2 R2 D2 F' R U' F U2 B' L' B' F2 D U
3rd solution (after 1-hour): B2 R' D2 B' U B D2 B' U D' B2 U' L B L2 U' L' U L2 B' L B L B2 U2 L2 U D' (28 moves)

Spoiler (Click to View)

Pre-scramble: U2 L2 U D'

2x2x3 block: B2 R' * B' U D'
Orient edges: U B2 U'
More EO + square: L B L2 U' L' U
All but 3 corners: L2 B' L B L B2
Correction: U2 L2 U D'

Insert at *: D2 B' U B D2 B' U' B